Motorists who get behind the wheel after taking drugs are to be targeted in a new road safety crackdown across Sussex and Surrey.

Legislation that comes into force on March 2 sets legal limits for how much of a substance – both illegal drugs and prescription medication – motorists can have in their system while driving.

A new device has also been approved that will allow officers at the roadside to test if a motorist has taken cannabis or cocaine.

The DrugWipe system allows officers to determine in less than 10 minutes whether motorists have the illegal substances in their body, using a swab from inside a driver’s cheek.

Officers no longer need to prove that a motorist is fit to drive – just that the motorist has an illegal level of drugs in their system while driving.

Any drivers who fail the tests will be arrested and taken to a police station where they will be asked to consent to a sample of their blood being taken.

That blood will then be sent away to be examined and if illegal levels of a drug are found, the motorist faces being prosecuted for drug-driving.

If the driver refuses to give consent, they face being prosecuted for the offence of failing to provide a sample of blood for analysis.

The change in the law is designed to make it quicker and easier for drug-drivers to be prosecuted – meaning more of the dangerous motorists can be removed from the streets.

Illegal drugs covered by the new rules include cannabis, cocaine, ecstasy, heroin and ketamine.

Medicinal drugs covered include diazepam, methadone and morphine. The limits for these drugs have been set after advice from a panel of medical experts, at the level where the substances begin to affect driving.

National statistics suggest one in six drivers who die in crashes in the UK have traces of illegal drugs in their systems - with many of them having taken both drink and drugs.

Motorists who have taken drugs can suffer from slower reaction times, an inability to concentrate, nausea, dizziness, fatigue, erratic and aggressive behaviour, hallucinations, panic attacks, paranoia and tremors.

A European study found that taking drugs increases the chance of you being involved in a serious or fatal crash by up to 10 times. Taking more than one drug or mixing drink and drugs can increase that chance by up to 30 times.

Inspector Stewart Goodwin, of Surrey and Sussex road policing unit, said, “Drug-driving is a widespread but often hidden menace across the country.

“You don’t have to be on illegal drugs to be unfit to drive - many prescription or over-the-counter drugs can also impair your ability to drive.

“In the same way that we take a zero tolerance approach to drink-driving, we will also not tolerate drug-driving.

“Driving under the influence of drugs puts not just the offenders and their passengers at risk but everyone else on the roads as well.

“We have officers out every day looking for drug-drivers but we also need the public’s help to catch them and get them off the roads.

“If you know or suspect someone has taken drugs and is driving, please contact us urgently – it could save lives.”

Sussex Police & Crime Commissioner Katy Bourne said: “One of the big challenges for the police has been, and continues to be, cracking down on drug-driving in the same way as they tackle drink-driving.

“Up until now, the drug-driving testing process has been a matter of professional medical judgement, which is open to challenge.

“That is why I welcome the new legislation that sets testable limits at the roadside for the most common drugs.

“These changes to the law will give the police the enforcement tools they need to protect road users from dangerous drivers and pursue those who have committed serious crimes. Crucially, this will improve the safety of everyone by taking drug drivers off our roads.”

Jason Fray, 29, was arrested at 2.30am on 20 December 2013 after officers found him parked next to the A29 at Billingshurst and suspected he could have been drug-driving.

Fray was ordered to prove that he was fit to drive by carrying out basic tasks such as walking in a straight line and standing on one leg.

It was clear that Fray could not complete the tasks properly so he was arrested. See the YouTube video to see him being tested and taken away for questioning.

Fray, of Rascals Close, Southwater, was convicted of being in charge of a vehicle while unfit through drugs. He was banned from driving for four months, fined £250 and ordered to pay £85 costs and a £25 victim surcharge.

Sean Thompson, 26, was arrested after he crashed his Ford Focus into a van in Petersfield Road, Midhurst, at 7.45am on 11 July 2014.

He was taking his young son to school and had already hit at least four parked cars on the journey before he crashed into the van, wrecking it and his vehicle.

When officers arrived he was trying to push his car at the scene. He had cocaine, ketamine and alcohol in his system.

Thompson, of Holmbush Way, Midhurst, pleaded guilty to driving while unfit through drugs. He was banned from driving for 29 months, given an eight week suspended sentence, ordered to do 80 hours of community service and ordered to pay £85 costs and an £80 victim surcharge.

People in Sussex can text officers on 65999 with the details of people they suspect of drink or drug driving or visit www.operationcrackdown.co.uk.

You can also contact the independent charity Crimestoppers anonymously on 0800 555111.

To keep up to date with officers looking for drink or drug drivers, follow #opdragonfly on Twitter.

If you know someone is driving while over the limit or after taking drugs call 999.